XXIV INTRODUCTION. 
more than three miles, and is at least four times as powerful as 
the voice of men and quadrupeds. 
Sweetness of voice and melody of song are qualities which in 
birds are partly natural and partly acquired. The facility with 
which they catch and repeat sounds, enables them not only to 
borrow from each other, but often even to copy the more diffi- 
cult inflections and tones of the human voice, as well as of 
musical instruments. It is remarkable that in the tropical 
regions, where the birds are arrayed in the most glowing 
colors, their voices are hoarse, grating, singular, or terrific. 
Our sylvan Orpheus (the Mocking-bird), the Brown Thrush, 
the Warbling Flycatcher, as well as the Linnet, the Thrush, 
the Blackbird, and the Nightingale of Europe, pre-eminent for 
song, are all of the plainest colors and weakest tints. 
The natural tones of birds, setting aside those derived from 
education, express the various modifications of their wants and 
passions ; they change even according to different times and 
circumstances. The females are much more silent than the 
males; they have cries of pain or fear, murmurs of inquietude 
or solicitude, especially for their young; but of song they are 
generally deprived. The song of the male is inspired by ten- 
der emotion, he chants his affectionate lay with a sonorous 
voice, and the female replies in feeble accents. The Nightin- 
gale, when he first arrives in the spring, without his mate, is 
silent ; he begins his lay in low, faltering, and unfrequent airs ; 
and it is not until his consort sits on her eggs that his en- 
chanting melody is complete: he then tries to relieve and 
amuse her tedious hours of incubation, and warbles more 
pathetically and variably his amorous and soothing lay. In a 
state of nature this propensity for song only continues through 
the breeding season, for after that period it either entirely 
ceases, becomes enfeebled, or loses its sweetness. 
Conjugal fidelity and parental affection are among the most 
conspicuous traits of the feathered tribes. The pair unite their 
labors in preparing for the accommodation of their expected 
progeny; and during the time of incubation their participa- 
tion of the same cares and solicitudes continually augments 
